Angularly adjustable drafting tables



Feb. 1, 1966 J. GELB 3,232,248

ANGULARLY ADJUSTABLE DRAFTING TABLES Filed March 19, 1963 5 Sheets-Sheet 1 J OHN GELB INVENTOR.

AGE T Feb. 1, 1966 J. GELB 3,232,248

ANGULARLY ADJUSTABLE DRAFTING TABLES Filed March 19, 1963 5 Sheets-Sheet 2 1 J OHN 651.5 INVENTOR.

Feb. 1, 1966 J. GELB 3,232,248

ANGULARLY ADJUSTABLE DRAFTING TABLES Filed March 19, 1965 5 Sheets-Sheet 5 JoH/v GELB INVENTOR.

G IE

AGENT Feb. 1, 1966 J. GELB 3,232,248

ANGULARLY ADJUSTABLE DRAF'IING TABLES Filed March 19, 1963 5 Sheets-Sheet 4.

JOHN G 51.5

INVENTOR.

Feb. 1, 1966 J. GELB 3,232,248

ANGULARLY ADJUSTABLE DRAFTING TABLES Filed March 19, 1963 5 Sheets-Sheet 5 JOHN 651.8

INVENTOR.

United States Patent 3,232,248 q ANGULAELY ADlUSTAliLE DRAFTIN G TABLES John Geih, 17251 Valerie SL, Van Nuys, Calif. Filed Mar. 19, 1963, Ser. No. 266,243 Claims. (Cl. 108-4) This invention pertains to drafting tables and more particularly to a type of drafting table in which the drawing board or surface may be locked in any angular position of adjustment.

In most drafting tables heretofore available, any angular adjustment of the drawing board has required several individual adjustments wtih the result that many drafts men and engineers leave the drawing board in the previously adjusted angular position rather than \go to the bother of changing it to a new position which may be more convenient for the individual draftsrnan or for the particular job in hand. Accordingly, one object of the present invention is to provide improved means for adjustably locking the drawing board in any desired angular position.

In addition to the disadvantages inherent in previous means for adjusting the angular position of drawing boards, the adjusting means have often been inconveniently located, requiring that the person doing the adjusting gain inconvenient access to wing nuts and thumb screws located under the drawing board. To overcome these difiiculties, another object of the present invention is to provide easily accessible means of adjustment.

An additional object is to provide means for locking the drawing board in any angular position and for actuating the lock, either for locking or unlocking, by a simple foot pedal.

Yet another object is to afford means for balancing the drawing board so that when it is unlocked it may be rotated from one angular position to another with very light pressure.

An additional object is to produce a structure in which the counterbalancing means will usually be located on the rear side of a vertical plane passing through the axis on which the drawing board is rotatably mounted.

A further object is to supply a construction that will permit the table to be. folded so that it may be placed out of the way in a narrow space.

Yet another object is to provide a supporting structure and system of levers and adjusting means that will allow the draftsman or engineer the free movement of his knees beneath the table.

This invention possesses many other advantages and has other objects which may be made more clearly apparent from a consideration of one embodiment of the invention. Such an embodiment will now be described in detail in order to illustrate the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims:

Referring to the drawings:

FIGURE 1 is an isometric view of the complete drawing table with the drawing board in one adjusted position;

FIG. 2 is a side elevation of the drafting boa-rd;

FIG. 3 is a section taken substantially on line 33 of FIG. 2;

FIG. 4 is an enlargement of the upper portion of the mechanism illustrated in FIG. 3 with some of the pivot able parts in angular positions which are different from those shown in FIG. 3;

FIG. 5 is a section taken substantially on line 55 of FIG. 4;

FIG. 6 is a view taken substantially on line 66 of FIG. 4;

3,232,248 Patented Fella. I, 1966 FIG. 7 is an inside view of the mechanism associated with the foot pedal for moving an operating link of the locking mechanism selectively in either longitudinal direction upon alternate operations of the foot pedal;

FIGS. 8, 9 and 10 show the components illustrated in FIG. 7 in different operating positions;

FIG. 11 is a section taken on line l1l1 of FIG. 9';

FIG. 12 is a side elevation, similar to FIG. 2, but showing the table partially folded; and

FIG. 13 is another side elevation showing the table completely folded.

In the presently preferred embodiment of the invention, two legs 1 and 2 arranged in an inverted V formation are received at their top ends in a 4-walled bracket 3 which is open at the bottom to receive the legs. A pair of struts 4 and 4- holds the lower portions of the legs in the desired spaced relationship. Two other legs 5 and 6 are similarly joined at the top and spaced at the bottom. Two bars 7 and 8 join the two end structures together in the manner illustrated in FIG. 1, bar '7 serving also as an optionally usable foot rest.

The leg 1 is integrally attached to the bracket 3, while the leg 2 is pivoted within this bracket as indicated at in FIGS. 2, 6, 12 and 13. The struts 4 and 4 are pivotally connected to the legs 1 and 2, respectively, as by a pivot 69' in the bracket 68' which is integral with leg 2. The two struts 4 and 4 are each pivoted within an oipen b-ottomed channel member 66' as shown at 67', and it will of course be understood that the same type structure is symmetrically arranged at the other end of the table. The construction just described permits the table to be folded when not in use as shown in FIGS. 12 and 13.

A shaft 9 is journaled for longitudinal movement in a pair of bearing blocks 11 and 11' which are integral with the elements or inner walls 25 and 25 of the housings 10 and 10' respectively, these housings being rigidly secured respectively to brackets 3 and 3, as shown in FIG. 3.

Two parallel elongated members 12 and 12, FIG. 4, are integrally joined near their centers to a tube 24 which surrounds the shaft 9, and the assembly thus formed is interposed on this shart between the housings 10 and 1h. Each of the elongated members that form a part of the H-shaped configuration just described comprises two arms 13 and 14 that extend out from the tube 24 in substantially opposite directions. The external end of 13 is pivotally attached at 17 to an elongated bracket or angle or channel 16 (FIGS. 2 and 12) that extends along one side of the table top or drawing board 15 and is integral therewith, and it will be understood that am 13' near the opposite end of the shaft is similarly con nected to the drawing board. The inside diameter of the tube 24, FIGS. 3 and 4, is considerably larger than the outside diameter of shaft 9 to avoid any possibility whatever of binding on the shaft.

An arm 18 is rotatably mounted on the shaft 9 between the housing 1d and the elongated member 12, and another identical lever 18' is similarly interposed between the elongated member 12' and the housing 10' at the other end of the shaft. The external end of arm 18 is pivoted at 19 to a link 2% whose opposite end is connected to the bracket 16 at point 21, which is located intermediate the pivot point 17 and the top end of this edge of the table 22, and it will of course be understood that a counterpart of link 20 similarly links arm 18' to the opposite edge 23 of the table.

Bearing block 11, which fits shaft 9 loosely, is integral with the element or end wall 25 of the housing 10 which is rigidly secured to the bracket 3 by means of which the legs 1 and 2 are fastened together. The bearing block 3 or boss 11' at the opposite end of the shaft is likewise integral with the end element 25' of the casing It will be clear that the table top, the arm 13, the lever 13 and the link constitute a four-sided link structure each of whose four sides is pivotally attached to the two adjoining sides of the linkage. As the table top is tilted to any desired angle, these four sides and their counterparts at the opposite end of the structure will each pivot with respect to their adjoining sides, but they may all of course be locked in any adjusted position by clamping the end element of housing 10, the lever 18 and the elongated member 12 together at one end of the shaft and similarly clamping their counterparts together at the opposite end of the shaft. This is actually accomplished in embodiments of my invention 'by'clamp-ing together as one stack all of these parts and counterparts and the intervening sleeve 24 between the end elements 25 and 25', this being effected of the shaft 9 which, as before mentioned, is slidably mounted in the bearings I1 and 11' in the housings 10 and 10'. The end of shaft 9 that-carries the housing It has an enlarged head 75 that fits into a counter-bored recess 76 in the hub 77 of member 37, and it is between this head and the nut 45 on the threaded opposite end of shaft 9 that the parts on the shaft are clamped, as hereinafter more fully explained.

The following parts, some of which have not heretofore been mentioned, are interposed in various positions between the housing 10 and the flange 26 of the elongated menrber 12, and it must be understood that the same elements are duplicated in symmetrical arrangement at the opposite end of the shaft. Three of these interposed elements are the plates 28, 29 and 30, FIG. 3, loosely pivotable on the shaft 9. These three plates are constrained against angular movement with respect to the bracket 3 by means of thepin 31 rigidly secured to the bracket 3 and slidably extending through appropriate apertures in each of the three-plates 28, 29 and 30. Another similar plate 32, which may be seen in FIGS. 2, 3 and 4, is interposed between the plate 28 and the end element or plate 25 of bracket 3, the plate 32 being constrained against relative angular movement with respect to lever 18 by means of the pin 33 passing through an appropriate aperture in the plate. As explained with respect to previously mentioned components of my table structure, the parts just described are of course duplicated at the opposite end of the shaft and in an order which is symmetrically the same. Another plate 34, like those just described, is interposed on the shaft between the plates 29 and 30, plate 34 being constrained against relative angular movement with respect to the elongated member 12 by means of a pin 35 integrally attached to arm 13 and slidingly passing through the plate 34, as indicated in the larger representation of these parts in FIG. 4.

Loosely fitting friction discs are mounted on shaft 9 between each of the following enumerated members: Bracket or housing 3 and plate 32; plate 32 and plate 28; plate 23 and lever-18; lever 18 and plate 29; plate 29 and plate 34; plate 34 and the flange 26, which is integral with the elongated member 12. These parts are of course symmetrically duplicated at the opposite end of the table.

The aforementioned plates and friction discs serve together to increase the resistance to relative movement between the various parts on shaft 9 when they are clamped together by means of the mechanism now about to be explained; thus, the resistance to angular movement between end wall 25 and lever 18 is not dependent upon the area of their facing surfaces, but upon these areas plus those of the two sides of the intervening plate 32 that is integrally tied to lever 18 and the areas of the circular portions of the two sides of plate 23 which is tied to end wall 25 by the pin 31; and the resistance to angular movement between end wall 25 and flange 26 of member 13 is similarly increased by the areas of the circular portions of plates'29 and 30 that are effectively joined to end wall 25 by pin 31, and by the circular areas of the two sides of the plate 34 which is connected to member 13 by pin 35. The same condition prevails with respect to the parts that are mounted on the opposite end of shaft 9. The total effective frictional areas of the various parts that are to be clamped against relative movement is thus multiplied many times by the interposition of the various plates and discs.

The relatively heavy plate 36, having a radially extending operating arm 37, is mounted on the shaft 9 for free longitudinal movement with narrow limits. This plate is also capable of angular movement on the shaft 9 within narrow limits which are determined by the engagement of the pin 38, FIGS. 4 and 5, with one end or the other of the arcuate slot 40 in the bearing block 11, this bearing block, as hereinbcfore mentioned, being integral with the inner wall 25 of the housing 10. This inner wall carries a plurality of substantially equally spaced sockets 41, and the plate 36 similarly carries a plurality of associated sockets 42, also equally spaced. A plurality of bars 43, whose opposite ends are ball shaped, are each interposed between one of the sockets 41 and an associated socket 42 on the member 36.

The end of the shaft 9 carries the housing 10' has athreaded periphery 44 which passes through the bearing boss 11' on the inner wall 25' of the housing 10, and a nut 45, in threaded engagement with this threaded end, acts as an abutment that bears against the shoulder 46 of the boss '11. It will be clear that screwing the nut 45 in one direction or the other around the threaded end 44 serves to alter the effective length of the shaft 9, the length being adjusted so that all the parts that are carried by the shaft'9 are tightly clamped together when the toggle bars 43 are in the locked over-center position shownin full lines in FIG. 4. When this condition prevails, the element or end wall 25 of housing 3, the lever 18, and all the other parts on shaft 9, including the sleeve 24 .that connects members 12 and 12', are all rigidly clamped against relative angular movement. How ever, if the plate 37 is moved so that its sockets .42 carry the togglebars 43 to the position shownin broken lines in FIG. 4, there will be no pressure on the end plate 37 and shaft 9 in the direction of arrow 47, and as a consequence there will be no pressure between the abutting nut 45 and the shoulder 46 of the bearing element 11' .at the opposite end of the shaft. Inasmuch as the drafting board and'all of the parts connected thereto are counterbalanced, the release. of the pressure of course permits all of the parts mounted on the shaft to turn freely. To provide such a counterbalance, the two arms 14 and14 of members 12 and 12' of the H- shaped'assembly are tied together by a cross member 48, the two ends of which are adjustably movable along these arms so that the position of the relatively heavy cross member 48 may be fixed thereon at a location in which it will counterbalance the drawing board. It should be clear that the aforementioned locking and unlocking is allelfected by a short angular movement of the arm 37 that moves the toggle bars between the full line and broken line positions shown in FIG. 4.

In order to limit the angular movement of the table top, the stationary housings 10 and 10' are provided with stationary abutments 71 and 71', respectively, that cooperate with stops on the angularly movable lever assemblies 18 and 18'. One of these stops '74, which limits the movement of lever 18 in a counterclockwise direction, may be seen in FIG. 6, but the one that limits its clockwise rotation is hidden behind the bracket 3. The abutments 71 and 71 are attached by means of their base ends 72 and '72 to the housings on which they are respectively mounted, and these abutments have overhanging ends 73 and 73 that are spaced from the angularly movable parts beneath them in order to provide positive clearance for all portions of these rotatable parts excepting the limiting stops.

A foot controlled actuator 49, FIGS. 1 and 2, moves arm 37 of plate 36 between its locked and unlocked positions shown in full and broken lines respectively in FIG. 6. This plate, as already explained, movably supports one end of each of the toggle bars. Motion is transmitted from the actuator 49 to the arm 37 by means of the interconnecting link 50.

The cover 51, shown on the actuator 49 in FIG. 2, has been removed in FIGS. 7 to 11, inclusive, in order to reveal the operating mechanism. In FIG. 7, the various parts are shown in the respective positions that they occupy when the foot pedal 61 has just been pressed down for the purpose of locking the drawing board or table top in its adjusted angular position. In order to show this mechanism still more clearly, the interconnecting link 56 of FIG. 2, which is normally connected to the arm 52 of the positionable lever 53, FIGS. 7 to 10, has been removed from the boss 54 at the end of arm 52 of the positionable lever 53. This lever is pivoted at 55 to the base plate 56 of the actuating assembly. Lever 53 carries two projections or lugs 57 and 58 that are equidistant from the center 55.

An operating lever 59, carrying the pedal 61 at its forward end, is pivoted at its opposite end at point 64) to the plate 56. The operating lever normally rests in the position shown in FIGS. 8 and 10, a position to which it is urged by any suitable keeper means such as an appropriately mounted weight or a spring. FIGS. 7 and 8 show a compression spring 62 suitably connected for this purpose.

A camming member 63 is pivoted at its lower end at a point 64 to the lever 5% intermediate its two ends. Member 63 is shaped somewhat like the profile of an urn and has opposite shoulders 65 and 66 that extend inward and in a direction generally away from the pivot point 64 toward a narrow neck 6'7. The top end of member 63 then flares outwardly to form two oppositely extending bulbous ends 6% and 69, which together with the neck portion 67, form hooks on opposite sides of the member.

In the positions in which we find members 59, 53 and 63 in FIG. 7, the boss or projection 57 rests against the neck 67 just below the lobe 68. As the foot is removed from pedal 61 on lever 5?, the immediate upward movement of member 63 in response to the action of spring 62, takes member 63 irom the position shown in FIG. 7 to the position shown in FIG. 8. During this upward movement 63 from the position shown in FIG. 7, the projection 57 will of course slide outward along the shoulder 65, thus camming member 63 to the right and causing lobe 69 to assume the position shown in FIG. 8 where the projection or lug 53S rests in the hook formed by shoulder 66 and the lobe 69.

The next downward movement of the operating lever 59 from the rest position shown in FIG. 8, will cause lobe 69 to pull down on boss This of course rotates member 53 clockwise from the angular position shown in FIGS. 7 and 8 to the different angular position pictured in FIG. 9 in which the arm 52 of lever 53 is considerably below the position pictured in FIGS. 7 and 8, as a comparison of these figures with FIG. 9 will readily show. This downward movement of arm 52 causes link 5%), which is normally pivotally attached to boss 54 on the end of arm 52, to move arm 37 of the locking member 36, FIGS. 6 and 4, from the locked to the unlocked angular position. When the locking mechanism has thus been released, the table top will readily move with only slight pressure to any angular position that may be desired. The pedal 61 must then be pressed down again, this action causing lobe 68 of cam 63 to pull down on boss 57, thus returning this boss and member 53:, to which it is attached, to the position shown in FIG. 7the position in which we found it at the beginning of our discussion of its cycle of operation.

Many alterations may of course be made from the illustrative embodiment of my invention hereinabove described, and the various elements may be replaced by other components performing the same or additional functions, and parts may be changed in position or transposed, all without departing from the broad spirit of my invention as succinctly set forth in the appended claims.

The inventor claims:

1. In a mechanism for moving a member successively in opposite directions upon successive movements of another member in a single direction, said mechanism comprising: a base; an operating lever pivoted at one end on said base; means urging said lever in one rotative direction; an angularly positionable member pivoted to said base, said positionable member having a pair of protruding lugs substantially equidistant from its pivotal axis; and a positioning element pivotally attached to said lever and having camming shoulders sloping toward each other from opposite edges of said element in a direction generally away from said elements axis of rotation to an intervening neck, said edges protruding outward beyond said neck to form hooks which individually act upon movement of said lever against the action of said means to pull on whichever lug is then most remote from said elements rotational axis, thus rotating said member to angular position in which the other lug will nest under the other hook, each of said lugs individually acting upon upward movement of said element under action of said means to slide outward and downward along the then engaging shoulder and exert a turning moment thereon to rotate said member to an angular position in which the opposite lug will nest against said neck.

2. In an angularly adjustable drafting table: a supporting structure having at the top of each side thereof a stationary bracket comprising an integral element facing the corresponding element of the opposite bracket; a shaft extending from one side of said structure to the other through said elements; a drafting board; an assembly comprising a pair of parallel spaced arms integrally joined to, and extending radially from, an intervening tube surrounding said shaft between said elements, the free ends of said arms pivotally attached to said drafting board near opposite ends of said board; a pair of levers each rotatably mounted on said shaft between one of said elements and a different end of said assembly; a pair of links each pivoted at one end thereof to the unsupported end of one of said levers; the other end of each of said links being pivotally attached to the drafting board near the side thereof to which the nearest of said parallel arms is pivoted; and releasable clamping means for clamping said elements, said levers and said assembly against relative angular movement, said clamping means comprising a pair of abutments on said shaft disposed near opposite ends thereof exteriorly of said elements, a first plate slidably mounted on said shaft between one of said abutments and the nearest of said elements, a second plate carried by said shaft between the other of said abutments and the other element for limited rectilinear and angular movement with respect to said shaft, and a plurality of angularly spaced toggle bars interposed between said other element and said second plate, said other element pivotal ly supporting one end of each of said bars, and said second plate pivotally supporting the other ends of said bars for angular movement between a first position in which said bars exert no longitudinal pressure on said other element and said second plate and a second over-center position in which the bars urge said other element in one direction and said second plate and shaft in an opposite direction to clamp said levers and said assembly between said other element and said one of said abutments.

3:. The combination of claim 2 in which said other element and said second plate support respectively opposite ends of said toggle bars in sockets spaced around the facing sides of said other element and said second plate.

4. In an angularly adjustable drafting table, a combination including: a pair of spaced supporting ele' ments; a shaft extending through said elements; an assembly comprising at least two spaced arms carried by said shaft for limited axial and angular movement with respect thereto; a drafting board so attached to said assembly that it will parallel said shaft; and releasable clamping means for clamping said elements and arms against relative angular movement, said clamping means comprising a pair of abutments on said shaft disposed near opposite ends thereof exteriorly of said elements, a first plate slidably mounted on said shaft between one of said abutments and the nearest of said elements, a second plate carrier by said shaft between the other of said abutments and the other element for limited rectilinear and angular movement with respect to said shaft, and a plurality of angularly spaced toggle bars interposed between said other element and said second plate, said other element pivotally supporting one end of each of said bars, and said second plate pivotally supporting the other ends of said bars for angular movement between a first position in which said bars exert no longitudinal pressure on said other element and said second plate and 5. The combination of claim 4 in which said otherelement and said second plate support respectively opposite ends of said toggle bars in sockets spaced around the facing sides of said other element and said second plate.

References Cited by the Examiner UNITED STATES PATENTS 1,956,546 4/1934 Froelich 108-2 2,655,417 10/1953 Zalkind '108-10 2,998,672 9/1961 Sautereau 1082 3,089,275 5/1963 Alabor 108-2,

FRANK B. SHERRY, Primary Examiner 

1. IN A MECHANISM FOR MOVING A MEMBER SUCCESSIVELY IN OPPOSITE DIRECTIONS UPON SUCCESSIVE MOVEMENTS OF ANOTHER MEMBER IN A SINGLE DIRECTION, SAID MECHANISM COMPRISING: A BASE; AN OPERATING LEVER PIVOTED AT ONE END ON SAID BASE; MEANS URGING SAID LEVER IN ONE ROTATIVE DIRECTION; AN ANGULARLY POSITIONABLE MEMBER PIVOTED TO SAID BASE, SAID POSITIONABLE MEMBER HAVING A PAIR OF PROTRUDING LUGS SUBSTANTIALLY EQUIDISTANT FROM ITS PIVOTAL AXIS; AND A POSITIONING ELEMENT PIVOTALLY ATTACHED TO SAID LEVER AND HAVING CAMMING SHOULDERS SLOPING TOWARD EACH OTHER FROM OPPOSITE EDGES OF SAID ELEMENT IN A DIRECTION GENERALLY AWAY FROM SAID ELEMENT''S AXIS OF ROTATION TO AN INTERVENING NECK, SAID EDGES PROTRUDING OUTWARD BEYOND SAID NECK TO FORM HOOKS WHICH INDIVIDUALLY ACT UPON MOVEMENT OF SAID LEVER AGAINST THE ACTION OF SAID MEANS TO PULL ON WHICH EVER LUG IS THEN MOST REMOTE FROM SAID ELEMENT''S ROTATIONAL AXIS, THUS ROTATING SAID MEMBER TO ANGULAR POSITION IN WHICH THE OTHER LUG WILL NEST UNDER THE OTHER HOOK, EACH OF SAID LUGS INDIVIDUALLY ACTING UPON UPWARD MOVEMENT OF SAID ELEMENT UNDER ACTION OF SAID MEANS TO SLIDE OUTWARD AND DOWNWARD ALONG THE THEN ENGAGING SHOULDER AND EXERT A TURNING MOMENT THEREON TO ROTATE SAID MEMBER TO AN ANGULAR POSITION IN WHICH THE OPPOSITE LUG WILL NEST AGAINST SAID NECK. 